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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 678 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.2?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 77 and take away the sum of its digits. What do you get?
  3. 3.1?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 30 and take away the sum of its digits. What do you get?
  5. 5.6?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?335 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 89 and take away the sum of its digits. What do you get?
  8. 8.?133 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 18 and take away the sum of its digits. What do you get?
  10. 10.?678 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?402 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.5?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.426? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?321 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?566 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.420? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.64? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 19 and take away the sum of its digits. What do you get?
  19. 19.108? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.6?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 44 and take away the sum of its digits. What do you get?
  22. 22.760? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 11 and take away the sum of its digits. What do you get?
  24. 24.Take 27 and take away the sum of its digits. What do you get?
  25. 25.?896 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 51 and take away the sum of its digits. What do you get?
  27. 27.?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 40 and take away the sum of its digits. What do you get?
  29. 29.Take 68 and take away the sum of its digits. What do you get?
  30. 30.8?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.11?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?436 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 35 and take away the sum of its digits. What do you get?
  34. 34.686? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 61 and take away the sum of its digits. What do you get?
  36. 36.30?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 41 and take away the sum of its digits. What do you get?
  38. 38.1?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.530? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.365? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 9
  2. 63
  3. 9
  4. 27
  5. 6
  6. 7
  7. 72
  8. 2
  9. 9
  10. 6
  11. 3
  12. 9
  13. 6
  14. 3
  15. 1
  16. 3
  17. 8
  18. 9
  19. 9
  20. 3
  21. 36
  22. 5
  23. 9
  24. 18
  25. 4
  26. 45
  27. 1
  28. 36
  29. 54
  30. 4
  31. 5
  32. 5
  33. 27
  34. 7
  35. 54
  36. 6
  37. 36
  38. 9
  39. 1
  40. 4

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